Satellite based global paging system

ABSTRACT

A satellite based paging communication system comprises a plurality of terrestrial stations capable of communicating the paging information with at least one satellite. The satellite(s), in turn, are capable of communicating the paging information to at least one terrestrial receiver or terrestrial station. Also included is at least one control station for determining where and how to deliver the paging information to one or more of a plurality of terrestrial receivers (pagers), at least some of which are capable of receiving the paging information from one or more of the satellites and one or more of the terrestrial stations.

TECHNICAL FIELD

This invention relates generally to paging communication systems, andmore specifically to wide geographic area paging systems, and isparticularly directed toward a satellite based global pagingcommunication system.

BACKGROUND

Historically, paging systems provided service to a limited geographicarea using a relatively high-power centralized transmitting site. Thisarrangement worked well in small cities and municipalities, but oftenproved unsuitable for large metropolitan areas. To adequately serve alarger geographic area, paging systems began to simulcast (i.e.,transmit the same message at substantially the same time) from severaltransmitters strategically positioned to provide wide-area coverage. Insuch a system, an individual having a selective call receiver (pager)could receive information anywhere in the metropolitan paging servicearea.

Today, the trend in paging communication is to provide even greatergeographic coverage. Nationwide paging systems are often contemplated inan attempt to provide paging messages to customers without regard towhere they are in the United States (for example). One known multi-citypaging system employs satellites to transmit paging messages to groundrepeaters in approximately eighty cities so that their customers can bepaged while travelling in any of the covered cities. Regrettably, thesemore recent paging systems suffer from paging traffic bottle-necksresulting from the required satellite-to-ground repeater link.Accordingly, a need exists for a paging communication system thatprovides everyone with convenient, reliable and efficient pagingservice.

SUMMARY OF THE INVENTION

Briefly, according to the invention, a paging communication systemcomprises at least one terrestrial station capable of communicating thepaging information with at least one satellite, and for communicatingthe paging information with at least one control station. Thesatellite(s) of this system are capable of communicating the paginginformation to at least one terrestrial receiver (e.g., pager) or to aterrestrial station. The system further includes at least one controlstation for determining where and how to deliver the paging information,and for directing the satellite(s) and/or the terrestrial stations toappropriately deliver the paging information to one or more terrestrialreceivers that may operate anywhere on a celestial body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of an orbiting satellite network in accordancewith the present invention.

FIG. 2 is a diagram illustrating system operation in accordance with thepresent invention.

FIG. 3 is a block diagram of a satellite of FIGS. 1 or 2.

FIG. 4 is an illustration of a satellite transmission footprint.

FIG. 5 is a diagram illustrating satellite communication paths andlinks.

FIGS. 6a-6c are flow diagrams outlining the operation of the satellitesof FIGS. 1, 2 or 5.

FIG. 7 is a block diagram of the control station of FIGS. 2 or 5.

FIG. 8 is a flow diagram illustrating the operation of the controlstation of FIG. 7.

FIG. 9 is a block diagram of a ground station in accordance with thepresent invention.

FIGS. 10a and 10b are flow diagrams illustrating the operation of theground station of FIG. 9.

FIG. 11 is a block diagram of a selective call receiver (pager) inaccordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Fundamentally, the present invention provides a worldwide communicationsystem designed to call (page) individuals having a selective callreceiver (pager). According to the invention, any contemporary selectivecall receiver manufactured by any paging manufacturer may be used in thepresent inventive system, which automatically adapts some portion ofitself to accommodate the pager(s) that are designated to receive apaging message. As will become hereinafter apparent, the accommodatingnature of the present invention serves the individual using the pager(paging customer), in that a broad range of operational flexibility isprovided in a system that can apportion system use fees based upon theneeds and instructions of those that use the system.

THE SYSTEM

Referring to FIG. 1, the inventive communication system of the presentinvention can be seen to be based on a network of satellites 102disposed about a celestial body 104. Preferably, seventy-sevensatellites are deployed in various orbits about the celestial body (orplanet) so as to be able to communicate a signal to a receiver anywhereon the planet. Of course, more or fewer satellites could be useddepending on the transmission capabilities of the satellites and thedesired communication coverage of the planet. Also, one or moregeostationary satellites could be used. According to the invention, theseventy-seven orbiting satellites are arranged in seven orbit planes toform a satellite network so as to provide communication regardless ofwhether the receiver is operating on a land mass, on a body of water, ortraveling by aircraft (provided that the aircraft is within the beam ofthe transmitting satellite).

Referring still to FIG. 1, three of the satellites are illustrated ascommunicating with a respective area 106a-106c of a land mass 108. Eacharea 106 is commonly referred to as the "footprint" of the transmittingbeam of each satellite. According to the present invention, eachsatellite is capable of transmitting paging information either to pagingreceivers, or to ground stations located within the footprint of aparticular satellite. In the preferred embodiment, the transmissionfootprint of each satellite comprises thirty-seven individualtransmission lobes as will become hereinafter apparent.

Within the satellite network, each satellite operates substantiallyindependently of the others; although the entire network is coordinatedby a centralized control facility. To provide a global paging systemcapable of accommodating the various operational protocols developed forpaging receivers and systems, the present invention adapts a portion ofitself for each paging event to the receiver (or receivers) designatedto receive the paging information. That is, for example, pagingreceivers operating in area 106a may receive paging information directlyfrom the satellite using Golay Sequential Coding (GSC). Simultaneously,paging receivers operating in area 106b can receive information from itssatellite, or a terrestrial base station (or both), using the POCSAGprotocol. Further, selective call receivers (pagers) operating in area106c may comprise existing tone-only or tone-and-voice paging receiversthat receive information relayed from the satellite through an existingcontemporary paging system. Thus, the present invention adapts thatportion of the system required to communicate with the pagers to becontacted. In this way, paging receivers provided by any manufacturermay be used in any part of the planet regardless of the fact that localareas of the planet may primarily use one paging protocol.

Referring to FIG. 2, a more detailed illustration of a portion of theglobal paging system is shown. As discussed in conjunction with FIG. 1,the present invention employs an orbiting space based backbone ofsatellites 102a-102f (6 shown) that orbit the planet in a plurality oforbits. A coordinating intelligence for the system is provided by acontrol station 110, which essentially comprises a large computingcenter (or other suitable information storage and processing center)that maintains a data library of every paging receiver registered tooperate on the global system, together with its preferred location toreceive paging messages, the preferred paging protocol, and otherparameters as may be necessary or desired to provide an effective pagingservice. In the preferred operation, the control station 110 receivesmessages from the satellite presently positioned above the controlstation by an antenna 112, which routes all incoming paging requestsfrom terrestrial base stations around the planet. Outgoing paginginformation is provided by an antenna 114 to the satellite network sothat the paging information may be directed to the appropriate pagingreceiver(s). Optionally, more than one control station could be used,however, the maintenance of the data base library could be moredifficult. In any event, the paging information is processed by thecontrol station 110 to include information as to where and how thepaging message should be delivered. This processing would includefrequency selection, protocol selection, and other information such aswhether the satellite should deliver the page directly or via aterrestrial station located in the approximate geographic area of thepaging receiver.

To initiate a page, individuals preferably contact a terrestrial station116 using telephone-type devices 118 through either a public or privatetelephone network. The terrestrial station 116 relays the paging messageby any appropriate protocol to a satellite (illustrated as 102a) viatransmission 120. Upon receipt of this information, satellite 102adetermines that it is not currently over the control station, andtherefore relays this information via the satellite network to anappropriate satellite for down-link transmission to the control station.Thus, in this example, the message would proceed from satellite 102a to102b, and then by inter-satellite link to satellite 102c. Since thecontrol station 110 resides within the transmission "footprint" ofsatellite 102c, the paging request is broadcast to the control station110 by a transmission 122.

Upon receipt of a paging request from the satellite network, the controlstation analyzes the identification (ID) code of the selective callreceiver to be paged to determine the service area requested by thepaging receiver. That is, each individual having a paging receiveroperative in the present inventive system is permitted to define theservice area in which he or she wishes to receive paging information.Thus, an individual may elect to receive paging information only withinone city or municipality. Others may wish to receive paging informationin multiple states. Still others may desire to receive informationacross entire countries, continents, or globally so that they mayreceive a paging message wherever they are in the world. The presentinvention contemplates that the central station 110 will maintain thisinformation for each selective call receiver registered to operatewithin the global system. In this way, the user has some control overthe billing amount by specifying the coverage area desired. That is, thefees customarily charged for using the paging systems are allocated uponthe extent of use specified by the paging receiver. In this way, costscan be fairly allocated among the several paging users depending uponthe activity required by the communication network. Of course, thebilling information itself is administered by the control station 110.Accordingly, the control station processes the incoming paging requestsand instructs the satellite network where the paging information shouldbe delivered based upon the instructions of the individual to be paged.Should this individual desire to travel or otherwise change his or herlocation for receiving messages (whether permanently or temporarily),that person must inform the paging service provider so that the controlstation's data library may be updated.

The control station 110 also determines how the paging message should bedelivered to the individual being paged by examining the data library toextract information identifying the preferred paging protocol(s) andoperational frequency(ies) of the selective call receiver to be paged.This information is also preferably provided by the paging serviceprovider at the time of registration of a pager on the global system. Ofcourse, this information may be updated from time to time if theindividual purchases another selective call receiver or is temporarilyusing a loaned pager during the repair of his or her registeredreceiver.

After determining where and how the paging information should bedelivered, the control station 110 returns the paging information to thesatellite network (satellite 102c in FIG. 2) via transmission 124. Inthis example, satellite 102c receives the paging information that is tobe directed to the area below the transmitting "footprint" of satellite102a. Accordingly, the paging information is routed through satellite102b to 102a, where the paging information is transmitted to a pagingreceiver 126 operating in the geographic region covered by the satellite102a. Preferably, as will be hereinafter described in further detail,each of the transmitting beams from the satellite comprises thirty-sevenindividual transmitting lobes; these lobes collectively representing thelargest "footprint" in which the satellite may communicate information.

For delivery of other paging messages, each terrestrial station 116 mayreceive information from the satellite network and route the paginginformation through local transmitting sites 130. These paging eventsmay be executed using the same protocol as the down-link transmissionfrom the satellite, or by translating the down-link protocol intoanother protocol (i.e., a protocol compatible with the selective callreceiver to be paged) so as to be adaptive to the paging receiver thatis intended to receive the paging message. Moreover, the terrestrialstations of the present invention, can be coupled to a contemporarylocal paging system 132, so as to provide paging messages to existingpaging receivers that are not capable of receiving paging messagesdirectly from the satellite network. Thus, a paging message received intransmission 134 by the terrestrial station 116' can be processed andconverted to paging information recognizable by the existing localpaging system 132. The converted paging information would be processedand disseminated to the transmitting sites 130 associated with the localsystem in the same manner as any local paging request. As is known, thetransmitting sites 130 may represent centralized transmitting sites fordifferent areas or cities, or may be simulcast transmitting sites toprovide contemporaneous transmission coverage to a wider geographicarea. In any event, the present invention contemplates communicatingdirectly from the satellite network in geographic areas that does notemploy ground based infrastructure or existing contemporary equipment,or terrestrial based relay stations to repeat or simulcast paginginformation on an appropriate paging protocol and frequency so as tosupport large municipalities. In this way, the terrestrial stations maybe used to off-load a portion of the paging traffic from the satellitenetwork, provide an alternate transmission point in circumstances wherethe paging receiver cannot correctly receive the paging informationdirectly from the satellite network (i.e., shadowed), or convert thedown-link protocol to a protocol and frequency compatible withcontemporary equipment.

Optionally, for those terrestrial stations and local systems physicallyresiding in the geographic area that the control station 110 isphysically located, an optional direct communication link 136 may beemployed to eliminate the need to go to the satellite network tocommunicate paging requests. As will be appreciated by those skilled inthe art, the transmitting footprints of the satellites 102 cover a widegeographic area. Those terrestrial stations and local systems within thesame operating footprint as the control station may therefore be coupleddirectly to the control station 110, since communications between suchsites would be repeated by the satellite above both of them.

THE SATELLITE(S)

Referring to FIG. 3, a satellite 102 is shown in block diagram form.Preferably, each satellite comprises a conventional low-orbitingsatellite such as those commercially available. Alternately, one or moregeostationary satellites may be used. Each satellite is placed in orbitby a suitable launch vehicle such as via America's Space ShuttleProgram. According to the invention, the preferred orbit is one that ishighly inclined, so as to provide effective global communicationcoverage. Lower inclination orbits may also be used, however, additionalsatellites would be required to achieve effective communicationcoverage. Once in orbit, a conventional solar cell array (not shown) isopened to provide power to the satellite 102. Following this, thesatellites are brought "on-line" using known techniques, such as, forexample, by using contemporary telemetry, tracking, and control (TT&C)protocols to form a satellite network.

Up-link transmissions are received by an up-link antenna 300 and decodedby an up-link receiver 302. The up-link receiver is coupled to aconventional satellite controller 304 and a paging controller 306 so asto appropriately route satellite control information and decoded paginginformation. The satellite controller 304 performs conventionalsatellite control functions such as orbit maintenance, positiontracking, and other appropriate functions as directed by controlpersonnel on the planet. The satellite controller 304 is also coupled tothe satellite's down-link transmitter 308, so as to provide anyinformation requested by ground based control personnel.

As shown in FIG. 3, the payload of the satellite 102 is occupied by thepaging controller 306 and a paging signal generator 310. Upon receipt ofpaging information, the paging controller must determine whether totransmit the paging message toward the planet (i.e., page a selectivecall receiver or send the page information to a ground station for relayto the selective call receiver), or to another satellite (for routing tothe control station or another satellite for transmission) in thesatellite network. Accordingly, an inter-satellite receiver 312 andtransmitter 314 are coupled to the paging controller 306 so that thepaging information can be appropriately routed. Additionally, thesatellite controller 304 is coupled to the inter-satellite receiver andtransmitter so as to communicate network control information as requiredfor the maintenance of the satellite network. Optionally, a singleinter-satellite transceiver may be used provided that its has asteerable antenna system to be able to communicate with its neighboringsatellites in the satellite network. Also, multiple inter-satellitetransceivers could be used provided that the satellites size and weightwere not adversely impacted, and so long as it is not cost prohibitive.

The paging controller 306 determines what and how to transmit in largepart in response to the type of information received. For example,up-link transmissions from a ground station should ordinarily be routedto the control station, while up-link transmissions from the controlstation usually contain information as to where and how the pagingmessage should be delivered. Inter-satellite communications can, ofcourse be either paging request or paging information, and the pagingcontroller determines appropriate routing chiefly by examining itspresent position (which is monitored by the satellite controller 304)and the destination of the request or information. Should the satellitecontroller determine that the received paging information should betransmitted toward the planet, the paging signal generator 310 is usedto provide the appropriate protocol and frequency selection. That is,the paging signal generator may deliver the paging information using anyknown paging protocol or any convenient protocol if transmitting to aground station or to the selective call receiver hereinafter described.For each paging transmission, this information is preferably provided bythe control station, or defaults to a predetermined protocol.Additionally, the down-link frequency selection is also made inaccordance with the delivery instructions provided by the controlstation.

Prior to the actual transmission, the paging controller 306 examines thepaging information to determine the desired communication coveragespecified by the individual to be paged. According to the invention,this information is provided to the paging controller by the controlstation and is provided to an antenna control system 316 to adjust the"footprint" of the satellite's transmission beam. This is preferablyaccomplished by controlling which of a plurality of individualtransmission lobes are activated. According to the invention, thedown-link antenna comprises one that has thirty-seven transmissionlobes. In this way, relatively fine control of the satellite'stransmitting signal may be achieved. Additionally, if the transmissionis directed toward a terrestrial station or the control station (asopposed to a pager) the transmitter power can be reduced under thecontrol (307) of the paging controller 306. In this way, the systemtakes advantage of the antenna gain available in the dish-type antennascommonly employed in ground based stations. The reduction in transmitterpower in these instances conserves energy within the satellite(s), whichof course, are powered by batteries charged by solar panels.

Referring to FIG. 4, a graphical depiction is provided to illustrate thepreferred satellite transmission "footprint". As previously mentioned,the preferred satellite down-link transmitting system includes anantenna having a plurality of individual lobes. In FIG. 4, the hexagonalcell format commonly used in conjunction with cellular telephone serviceis used for convenience to illustrate to user selectable coverage aspectof the present invention. Those skilled in the art will appreciate thatthe actual transmission patterns of the satellite's antenna lobes do notcomprise perfect hexagons.

According to the invention, each individual is permitted to specify theareas in which he or she will receive paging messages. For example, ifan individual only wished to receive pages at home or in the office,areas 17 and 12 may be specified. In an alternate example, widercoverage may be provided by specifying areas 12-14, 18-20, and 25-26. Infact, any arrangement of coverage areas (contiguous or non-contiguous)may be provided including receiving paging information under the entirethirty-seven transmitting lobes of one satellite and some or all of thelobes of any of the other satellites in the entire satellite network. Inthis way, paging service may be provided using any paging format orprotocol on a global coverage basis for those desiring such coverage,while local area coverage may be may also be provided to those desiringonly local coverage and the lower operational costs associatedtherewith.

The satellites' communication abilities may be further described inconjunction with FIG. 5. Three satellites are shown engaged in bothinter-satellite communication and terrestrial up-link/down-linkcommunication. The illustrated satellites (N-1, N, and N+1) may besatellites in the same orbiting plane, or be represent one satellite inthree contiguous orbit planes. In either event, inter-satellitecommunications is the same. That is, each satellite is capable ofcommunicating with a previous and next satellite in the same orbitingplane, and with a satellite in a previous and next orbit. Thisarrangement provides a satellite network capable of effectivelydisseminating paging information to any point on the orbited celestialbody.

As shown in FIG. 5, satellite N communicates information with satelliteN-1 via link N, and with satellite N+1 via link N+1 (and so on). Thesetransmissions are made using the inter-satellite transmitter andreceiver (or optional transceiver) discussed above in conjunction withFIG. 3. In one embodiment, conventional microwave communication is usedfor the inter-satellite links, although known optical media (e.g.,lasers) may be used if not cost prohibitive.

Also illustrated in FIG. 5 are the fundamental up-link and down-linkcommunication abilities of the satellite network of the presentinvention. As shown, satellite N-1 may communicate with a terrestrial orground station that may in turn be coupled to an existing conventionalpaging network. The communication path used for terrestrial stations(Beam N-1) is usual a bidirectional path so that paging requestsreceived via a telephone-type network may be forwarded to the controlstation, while paging information can be received and processed from thesatellite network. Optionally, if desirable in any particularimplementation, a terrestrial station may utilize only an up-link or adown-link communication path. Satellite N is shown communicatingdirectly with a pager via Beam N. This provides communication in thosearea of the planet that does not have existing equipment and where itwould be un-economical or otherwise undesirable to locate a groundstation. A paging receiver suitable to receive paging informationdirectly from the satellite network is hereinafter described. Anotherfundamental communication page is illustrated as Beam N+1 from satelliteN+1. In this example, satellite N+1 is the satellite over the controlstation, and therefore, is the satellite ultimately responsible forfinally communicating paging requests to the control station, and forinitially receiving paging information from the control station.According to the invention, the inter-satellite and up-link/down-linkcommunication capabilities of the satellite network permit an individualhaving a paging receiver to receive paging messages anywhere on thecelestial body.

Referring to FIGS. 6a-6c, the preferred operation of the satellitesbegins with decision 600, which determines whether information has beenreceived from a ground station. An affirmative determination fromdecision 600 generally means that a paging request has been transmittedfrom one of the ground stations and should be directed to the controlstation for a determination of where and how the paging message shouldbe delivered. Accordingly, decision 602 determines whether the satelliteis presently over the control station. This determination isaccomplished using known mechanisms within the satellite controller byexamining the current position of the satellite over the planet andcomparing this information with the known location of the controlstation. If the determination of decision 602 is that the satellite iscurrently over the control station, the information is transmitted tothe control station (step 608) (This transmission may optionally be madeat a lower transmitter power since the control station employs a highgain dish-type antenna). Conversely, a negative determination ofdecision 602 results in the information being transmitted to anothersatellite. As previously discussed, the other satellite may either be inthe same orbiting plane or an adjacent orbiting plane as that of thesatellite that first received the information. In this way, theinformation progresses through the satellite network until it isdirected to the control station.

Assuming that the determination of decision 600 is that information wasnot received from a terrestrial or ground station, the routine proceedsto decision 610, which determines whether information has been receivedfrom the control station. According to the invention, the controlstation processes each paging request and makes determinations as towhere and how the paging message should be delivered. Therefore, thecontrol station typically up-links all paging information to thesatellite network for appropriate distribution through the satellitenetwork and back to the planet (either directly or by way of aterrestrial or local station). Thus, should the determination ofdecision 610 be that the information was received from the controlstation, the routine proceeds to decision 612, which determines whetherthe satellite is presently over the identified pager (or pagers) that isto receive the paging message. If not, the routine proceeds to step 614,where the information is transmitted to another satellite in the sameorbiting plane or an adjacent orbiting plane so as to deliver the pagingmessage to the paging receiver as directed by the control station.Conversely, if the determination of decision 612 is that the pager iswithin the communication abilities of the satellite, the routineproceeds to step 616, which transmits the paging message either directlyto the pager or to a ground station or local station as determinedappropriate by examination of the instructions of the control station.(As previously mention, transmissions toward a ground station may bemade with a lower satellite transmitter power since the preferred groundstation employs a high gain antenna).

Assuming that the determination of 610 is that information was notreceived from the control station, the routine proceeds to decision 618,which determines whether the information was received from anothersatellite. If so, decision 620 determines whether the information isdirected towards a paging receiver. That is, aside from generalsatellite control and orbit maintenance information, an inter-satellitecommunicate is generally information being directed towards the controlstation, or information from the control station being directed towardsone or more pagers. Thus, a negative determination of decision 620causes decision 622 to determine whether the satellite is currently overthe control station. If not, the information is transmitted to yetanother satellite in the satellite network so as to direct theinformation to the control station (step 624). However, if the satelliteis over the control station, step 625 transmits the information to thecontrol station for processing as previously discussed. Conversely, ifthe determination of decision 620 is that the information is directedtowards a pager, decision 623 determines whether the information isdirected for the area within its beam "footprint". If not, the pager (orpagers) that are to receive this message are not beneath the satellite,and therefore, the paging information must be forwarded to anothersatellite for delivery (step 624). However, if the determination ofdecision of 623 is that the information is directed for the geographicarea below, the routine proceeds to step 626, where the antenna beam(footprint) is selected in accordance with the instructions provided bythe control station. As previously mentioned, the control stationinstructions are generated primarily based upon the coverage wishes anddesires of the individual users, and determines (in part) the amount ofbilling that will be generated for the paging event. After the beampattern of the satellite has been appropriately selected, the preferredpaging transmit frequency and protocol are selected (steps 628 and steps630) in accordance with the preferred message delivery request specifiedby the paging subscriber and commanded by the control station. Oncethese adjustments have been made, the information is transmitted (step632) towards the planet to be received either by the paging receiver orby a ground station that will rebroadcast the information in anappropriate format. Thus, the satellite and/or associated ground stationwill adapt its transmission and signalling format for the convenience ofthe paging receiver so that the receiver of any manufacturer can operatein the present system.

THE CONTROL STATION(S)

Referring to FIG. 7, a block diagram of the control station 110 isshown. The control station 110 receives information from the satellitenetwork via a receive antenna 112 and a receiver 700. This informationis routed to a controller 702, which in one embodiment comprises anMC68030 microcontroller manufactured by Motorola, Inc., or itsfunctional equivalent. The controller 702 operates to process pagingrequests to determine where and how the paging messages should bedelivered. This is accomplished primarily by examination of a datalibrary stored in a memory 704, which contains a suitable amount of typeof memory to store operating characteristics and instructions for eachreceiver registered to operate on the global paging system. Afterprocessing this information, the paging message is forwarded to atransmitter 706 for transmission via an antenna 114 to the satellitenetwork. Optionally, satellite control circuitry 708 may be residentwithin the central station and each terrestrial station to providesatellite orbit maintenance, position tracking, and other controlfunctions well known in the art for maintenance of the satellitenetwork. Alternately, satellite control maintenance may take place fromone or more another facilities designed to track and maintain thesatellite network. As previously discussed, for those terrestrialstations and local systems within the same physical area of the controlstation 110, an optional direct link 136 may be used by the presentinvention to off load satellite up-link and down-link traffic in thenearby geographic area.

Referring to FIG. 8, the routine followed by the control station 110 toprocess a paging request is shown. In step 800, a paging request isreceived by the control station from the satellite network. Followingthis, the controller 702 examines the memory 704 to determine the amountof paging coverage desired by the individual user. This, in part, willdetermine the billing amount for the paging event about to be broadcast.Also, the memory 704 contains information specified by the user fordefining the preferred paging protocol that should be used (step 804).Additionally, the paging frequency has preferably also been specified bythe paging user (step 806). Finally, the control station 110 determineswhether a terrestrial station should be used (step 808) to relay theinformation (either directly or through a conventional local system) tothe paging receiver. After these determination are made in accordancewith the instructions of the paging user and applicable locationinformation, the paging information and appropriate control informationis transmitted to the satellite network (step 810). In this way, thepaging receiver can receive a paging message directly from thesatellite, from a terrestrial station (or both) or from an existinglocal system using any of the known (standard) paging formats so thatthe entire satellite network becomes transparent to the paging user.

THE GROUND STATION(S)

Referring to FIG. 9, there is shown a block diagram of a terrestrial orground station 116 in accordance with the present invention. Down-linkinformation from the satellite network is received by an antenna 900 anddecoded by a receiver 902 of the ground station control 904. The groundstation controller 904 processes this information to extractinstructions from the control station as to the frequency and pagingprotocol that should be used in the delivery of the paging message tothe paging receiver. The controller 904, in one embodiment, maycomprises an MC68030 microcontroller manufactured by Motorola, Inc., orits functional equivalent. In accordance with the instructions from thecontrol station, the ground station controller 904 controls the protocolconverter 906 so as to select (or convert) to the appropriate protocol.Fundamentally, the protocol converter 906 operates to decode whateverformat was used by the satellite for the down-link message to extractthe paging message. Once the message has been extracted, it can bere-encoded in any selected paging protocol for subsequent transmissionto the paging receiver. Typically, this is accompanied via transmissionsfrom the transmit sites 130 associated with the terrestrial station, orby conversion of the paging message into a standard paging request to anexisting local station 132 as has been previously discussed. In additionto selecting the appropriate protocol, the ground station controller 904controls one or more transmit site controllers 908, which operate tocontrol the local transmit sites 130 in parameters such as frequencyselection, the number of sites that should transmit the signal, andwhether the signal should be simulcast from several transmitters as isknown in the art.

To generate a paging request, the ground station 116 incorporates apaging terminal 910 to receive messages from public or private telephonenetworks 912. The paging terminal operates the format and generates theappropriate request, which is forwarded to the ground station controllerbefore being transmitted to the satellite network via a transmitter 914and an up-link antenna 916. Optionally, as discussed in conjunction withthe control station, satellite control circuitry 918 may be incorporatedinto the terrestrial or ground stations to provide control andmaintenance of the satellite network.

Referring to FIGS. 10a and 10b, the preferred sequence of operations ofthe ground station 116 is illustrated. The routine begins in step 1000,which determines whether a paging request has been received. If so, therequest is properly formatted and transmitted to the satellite networkfor routing to the control station as has previously been described(step 1002). Conversely, if the determination of decision 1000 is that apaging request has not been received the routine proceeds to decision1004, which determines whether paging information has been received fromthe satellite network. Is so, decision 1006 determines whether thepaging information should be processed to represent an existing localpaging request and forwarded to a contemporary local station fortransmission. If so, the routine proceeds to step 1008, where thedown-link protocol used from the satellite is converted into theappropriate "standard" paging format for the existing contemporary localsystem (which is sent to the local system in step 1010 fortransmission).

Assuming that the determination of decision 1006 is that the paginginformation is not for a local station, the routine proceeds to step1012 for transmission from the transmit site(s) associated with theterrestrial station. After examining the instructions from the controlstation, the terrestrial station operates to select the paging protocolor convert from the down-link protocol to appropriate paging protocolfor the convenience of the paging receiver. Following this, thepreferred paging frequency is selected in accordance with the user'sinstructions (step 1014). Next, the number and location of transmitsite(s) to be used to broadcast the message are determined (step 1016)prior to transmission of the paging information to the paging receiver(1018).

THE PAGING RECEIVER(S)

Referring to FIG. 11, there is shown a block diagram of a pagingreceiver 126 in accordance with the present invention. Operationally,the paging messages are received by an antenna 1100, which is forwardedto an antenna switch 1102. The position of the switch will route thereceived information either through the satellite compatible "front-end"portion or the terrestrial station compatible "front-end" of the pagingreceiver 126. Thus, one output of the switch 1102 routes the receivedsignal to an RF amplifier 1104, which preferably amplifies signal in the1.5 GHz satellite frequency range. The amplified signals are applied toa mixer 1106, which receives a local oscillator signal from synthesizercircuitry 1108. To receive satellite based signals, the local oscillatorsignal is multiplied by a multiplier 1110 so as to appropriatelydemodulate the high frequency satellite signal. The mixer 1106 providesa first IF signal 1112 to an IF filter 1114, which is coupled to asecond mixer 1116. The mixer 1116 accepts another local oscillatorsignal 1118 from the synthesizer circuitry 1108 and provides a second IFsignal 1120, which is filtered by an IF filter 1122. According to theinvention, this second IF stage is common to both the terrestrial andreceiver recovery section of the paging receiver.

To receive terrestrial based signals, the antenna switch 1102 may routethe signal to an RF amplifier 1104', which comprises an amplifierdesigned to amplify frequencies in the UHF or VHF frequency range. Thissignal is mixed by a mixer 1106' to provide a first IF signal 1112' toan IF filter 1114'. The filter signal is again mixed in a second mixer1116' by another local oscillator 1118' from the synthesizer circuitry1108. This again produces the common second IF signal 1120, which isfiltered by the second IF filter 1122. In either event, the filteredsecond IF signal is processed by a detector 1124, which recovers thepaging information for further processing by a microcontroller 1126. Inone embodiment of the invention, the microcontroller 1126 may comprisean MC68HC11 microcomputer manufactured by Motorola, Inc., or itsfunctional equivalent.

To receive paging informations from any of the several known "standard"land based systems, a terrestrial station of the present invention, ordirectly from a satellite, the microcontroller 1126 selects a decodingprotocol (some pagers may use only one protocol) and controls thesynthesizer circuitry 1108 so as to appropriately mix these signals downin the second IF signal 1120. Additionally, since the synthesizercircuitry 1108 is programmed by the microcontroller 1126, the pagingreceiver 126 of the present invention can scan several frequenciesmerely by reprogramming the synthesizer circuitry in any of the knownsynthesizer programming techniques known in the art.

According to the invention, the paging receiver 126 preferably operatesin an automatic mode to first scan for a terrestrial based transmitterbefore relying upon the satellite network for direct transmission in anycity or geographic area that offers a ground based transmitting site(s).By first scanning for a terrestrial based station, priority is given tothe terrestrial channels. That is, for the paging receiver 126 describedherein, when the paging customer specifies the area or areas in which heor she desires to receive paging messages, if a terrestrial basedtransmitting site is available to deliver these messages they will beused. This practice "off-loads" the satellite network and improvessystem wide paging message through-put. In one preferred scanningtechnique, the paging receiver 126 operates to alternately scan forterrestrial and satellite signal. In another embodiment, all (or aportion) of known terrestrial signals could be first scanned, followedby the paging receiver's scanning of one or more satellite channels.

Of course, the automatic mode discussed above could be over-ridden infavor of a manual mode. To do this, the microcontroller 1126 receivesinstructions and commands from user controls 1128, which includeconventional functions such as "read" and "lock" function selections andother known user controls commonly employed on contemporary pagers.Additionally, one such user control (i.e., a Satellite/Terrestrialswitch) may operate to force the microcontroller 1126 to control theswitch 1102 such as to permanently select either the satellite based orthe terrestrial based demodulating sections of the paging receiver 126.In this way, the paging customer (user) is given more control over howpaging messages are received.

The automatic mode could also be over-ridden by instructions from thecontrol station, which are incorporated into a paging message. Thisprocedure may be preferably employed to re-route the delivery of pagingmessages to ease a congested paging traffic path or to accommodate thepaging user when their preferred (specified) message delivery path hasmalfunctioned.

When the message is received, it is customary for the microcontroller1126 to activate an alert circuit 1130, which may include silent alert,visual alert, or audible alert as is known in the art. Data messages maybe displayed upon any suitable display means 1132, while tone, ortone-and-voice messages are presented to the user via a speaker 1134(after amplification and filtering through audio circuits 1136). In thisway, the paging receiver 126 of the present invention may receive pagingmessages directly from the satellite network or a terrestrial basedground station. Additionally, the paging receivers manufactured by othermanufactures may operate on the present inventive system since thesystem adapts that portion of itself necessary to deliver any pagingmessage in any paging format anywhere in the world.

What is claimed is:
 1. A paging communication system,comprising:terrestrial based communication means for communicatingpaging information to a control means and to at least one of a pluralityof selective call receivers, the terrestrial based communication meansalso for communicating the paging information to a satellite basedcommunication means; the satellite based communication means forcommunicating the paging information to at least one of the plurality ofselective call receivers and at least some of the terrestrial basedcommunication means; the control means for determining where to deliverthe paging information and operational parameters and operationalprotocols for delivery of the paging information to the plurality ofselective call receivers; and the plurality of selective call receivers,at least some of which receive the paging information from the satellitebased communication means and the terrestrial based communication means.2. The system of claim 1, wherein the satellite based communicationmeans comprises a plurality of satellites arranged in a satellitenetwork orbiting a celestial body.
 3. The system of claim 1, wherein thesatellite based communication means comprises at least one geostationarysatellite orbiting a celestial body.
 4. The system of claim 1, whereinthe satellite based communication means adapts itself to communicate thepaging information to one of the plurality of selective call receiversin accordance with the operational parameters and the operationalprotocols, the operational parameters and the operational protocolsdetermined in response to instructions provided by an individualoperating the one of the plurality of selective call receiversdesignated to receive the paging information.
 5. The system of claim 4,wherein the satellite based communication means adapts itself tocommunicate the paging information to the plurality of selective callreceivers in accordance with the operational protocols, the operationalprotocols comprising at least a paging communication protocol.
 6. Thesystem of claim 4, wherein the satellite based communication meansadapts itself to communicate the paging information to the plurality ofselective call receivers in accordance with the operational parameters,the operational parameters comprising at least a paging communicationfrequency.
 7. The system of claim 1, wherein the terrestrial basedcommunication means includes means for converting the paging informationreceived from the satellite based communication means to accommodate oneof the plurality of selective call receivers designated to receive thepaging information.
 8. The system of claim 1, wherein some of theterrestrial based communication means is coupled to contemporary pagingcommunication equipment.
 9. The system of claim 1, wherein the pluralityof selective call receivers operate to monitor the terrestrial basedcommunication means and the satellite based communication means.
 10. Thesystem of claim 9, wherein the plurality of selective call receiversoperate to monitor the terrestrial based communication means and thesatellite based communication means by automatically scanning radiofrequency channels used by the terrestrial based communication means andthe satellite based communication means.
 11. The system of claim 10,wherein priority is given to the radio frequency channels used by theterrestrial based communication means while automatically scanning theradio frequency channels used by the terrestrial based communicationmeans and the satellite based communication means.
 12. The system ofclaim 1, wherein the control means includes a memory means for storingat least information representing a preferred paging area for at leastsome of the plurality of selective call receivers operative in thesystem.
 13. The system of claim 1, wherein the control means includes amemory means for storing the operational parameters, wherein theoperational parameters comprise at least information representing apreferred paging frequency for at least some of the plurality ofselective call receivers operative in the system.
 14. The system ofclaim 1, wherein the control means includes a memory means for storingthe operational protocols, wherein the operational protocols comprise atleast information representing a preferred paging protocol for at leastsome of the plurality of selective call receivers operative in thesystem.
 15. The system of claim 1, wherein the control means comprisesmemory means for storing the operational parameters and the operationalprotocols, and wherein the control means determines where and how todeliver the paging information to the plurality of selective callreceivers in accordance with the operational parameters and theoperational protocols stored within the memory means.
 16. A pagingcommunication system, comprising:a plurality of terrestrial receivers,at least some of which receive paging information from at least onesatellite and from at least one of a plurality of terrestrial stations;the plurality of terrestrial stations for communicating the paginginformation with the at least one satellite, and for adapting the paginginformation so as to be compatible with at least one of the plurality ofterrestrial receivers, wherein the at least one of the plurality ofterrestrial receivers operates to monitor the at least one of theterrestrial stations and the at least one satellite; the at least onesatellite for communicating the paging information to the at least oneof the plurality of terrestrial stations and at least one controlstation, and further for directly transmitting the paging information tothe at least one of the plurality of terrestrial receivers; and the atleast one control station for determining where to deliver the paginginformation and operational parameters and operational protocols todeliver the paging information to the plurality of terrestrialreceivers.
 17. The system of claim 16, wherein the at least one of theplurality of terrestrial receivers operates to monitor the at least oneof the terrestrial stations and the at least one satellite byautomatically scanning radio frequency channels used by the at least oneof the terrestrial stations and the at least one satellite.
 18. A methodfor providing a message to one or more areas on a celestial body,comprising the steps of:at any of a plurality of terrestrialstations:(a) receiving the message; (b) transmitting the message to acontrol station; at the control station:(a) receiving the message; (b)determining where to deliver the message and operational parameters andoperational protocols for delivering the message; (c) transmitting themessage to at least one of a plurality of satellites orbiting thecelestial body; at any of the plurality of satellites:(a) receiving themessage from the control station; (b) determining whether to transmitthe message toward the celestial body or another one of the plurality ofsatellites; (c) transmitting the message in accordance with thedetermination of step (b).
 19. The method of claim 18, wherein thecontrol station step of determining where and operational parameters andoperational protocols to deliver the message comprises the steps of:(i)examining a memory means to extract information representing preferredmessage reception instructions comprising the operational parameters andthe operational protocols for delivering the message; and (ii) formingmessage delivery instructions based at least in part upon theinformation representing preferred message reception instructions. 20.The method of claim 18, wherein the step of transmitting the message atany of the plurality of satellites comprises transmitting the message tothe control station when the message is directed toward the controlstation and the control station is within the communication abilities ofthe one of the plurality of satellites transmitting.
 21. The method ofclaim 18, wherein the step of transmitting the message at any of theplurality of satellites comprises transmitting the message to theanother one of the plurality of satellites when the message is directedtoward the control station but the control station is not within thecommunication abilities of the one of the plurality of satellitestransmitting.
 22. The method of claim 18, wherein the step oftransmitting the message at any of the plurality of satellites comprisestransmitting the message toward the celestial body when the message isdirected toward one of the terrestrial stations that is within thecommunication abilities of the one of the plurality of satellitestransmitting.
 23. The method of claim 18, wherein the step oftransmitting the message at any of the plurality of satellites comprisestransmitting the message to another satellite when the message isdirected toward one of the terrestrial stations but the one of theterrestrial stations is not within the communication abilities of theone of the plurality of satellites transmitting.
 24. The method of claim18, wherein the step of transmitting the message at any of the pluralityof satellites comprises transmitting the message toward the celestialbody when the message is directed toward a selective call receiver thatis within the communication abilities of the one of the plurality ofsatellites transmitting.
 25. The method of claim 18, wherein the step oftransmitting the message at any of the plurality of satellites comprisestransmitting the message to the another one of the plurality ofsatellites when the message is directed toward a selective call receiverbut the selective call receiver is not within the communicationabilities of the one of the plurality of satellites transmitting. 26.The method of claim 18, which includes the step at any of the pluralityof terrestrial stations of (c) receiving the message from at least oneof the plurality of satellites and transmitting the message to one ormore selective call receivers.
 27. The method of claim 26, whichincludes the step of adapting the message to be compatible with the oneor more selective call receivers in accordance with the operationalparameters and the operational protocols determined by the controlstation prior to the transmission thereof.
 28. The method of claim 18,which includes the steps at one or more selective call receivers of:(a)determining whether to monitor at least one of the plurality ofterrestrial stations and at least one of the plurality of satellites;(b) operating in accordance with step (a) to receive the message.
 29. Acommunication system operative on a celestial body having a plurality ofindividuals thereon, at least one of the plurality of individuals havinga selective call receiver for receiving a message from at least oneterrestrial station and from a satellite network comprising at least onesatellite orbiting the celestial body, the communication systemcomprising:the at least one terrestrial station positioned on thecelestial body for communicating the message received from the satellitenetwork orbiting the celestial body to the at least one of the pluralityof individuals having the selective call receiver and for communicatingthe message to a control means via the satellite network; the controlmeans for receiving the message, determining where and operationalparameters and operational protocols for delivering the message to theat least one of the plurality of individuals having the selective callreceiver, and for transmitting the message to the satellite networkorbiting the celestial body; and the satellite network comprising the atleast one satellite orbiting the celestial body and arranged tocommunicate the message toward at least a portion of the celestial bodyfor reception by one of a group consisting essentially of the at leastone of the plurality of individuals having the selective call receiverand the at least one terrestrial station.
 30. The system of claim 29,wherein the control means includes a memory means for storinginformation representing user defined message reception preferences, theuser defined message reception preferences including the operationalparameters and the operational protocols.
 31. The system of claim 29,wherein each of the at least one satellite in the satellite networkincludes means for adjusting transmission characteristics thereof so asto transmit the message only to desired portions of the celestial body.32. The system of claim 29, wherein at least some of the at least oneterrestrial station is operably interconnected with contemporary pagingequipment.
 33. The system of claim 29, wherein each of the at least onesatellite in the satellite network includes means for reducingtransmitter power when transmitting information to the control means orany of the plurality of terrestrial stations.
 34. The system of claim29, wherein the selective call receiver of the at least one of theplurality of individuals is constructed and arranged to receive paginginformation in accordance with one or more of the operational protocols.35. The paging communication system of claim 1, wherein each of the atleast some of the plurality of selective call receivers receiving thepaging information from the satellite based communication means and theterrestrial based communication means comprises:first receiving meansfor receiving the paging information from the satellite basedcommunication means; second receiving means for receiving the paginginformation from the terrestrial based communication means; receivercontrol means for controlling the first receiving means and the secondreceiving means to provide priority operation to the second receivingmeans for receiving the paging information from the terrestrial basedcommunication means to attempt to receive the paging informationtherefrom before attempting to receive the paging information from thesatellite based communication means.
 36. The selective call receiver ofclaim 35, wherein the receive control means includes means forover-riding the priority operation provided to the second means forreceiving the paging information from the terrestrial basedcommunication means.
 37. The selective call receiver of claim 36,wherein the means for over-riding the priority operation provided to thesecond means for receiving the paging information from the terrestrialbased communication means is responsive to operator entered commands.38. The selective call receiver of claim 36, wherein the means forover-riding the priority operation provided to the second means forreceiving the paging information from the terrestrial basedcommunication means is responsive to commands contained in the paginginformation.